Nanotags for authentication

Abstract

A method for creating a nanostructure surface, comprises creating a nanostructure master having a surface being the negative of a shape that, when illuminated with a predefined illumination, provides a unique optical pattern; and creating nanostructure molds from the nanostructure master, wherein each nanostructure mold has a negative of the master surface which, when illuminated with the predefined illumination, provides the unique optical pattern, which may be a hologram. A nanotag may incorporate an image for identification and a unique pattern that can be identified for authentication.

What is claimed is: 
     
       1. A nanotag comprising a dual layer metallic surface having an inner layer part and an outer layer part, said outer layer part of said dual layer metallic surface comprising nanostructures which, when illuminated with a predefined illumination, provide a predetermined unique optical pattern, wherein a first of said nanostructure dual layers is on a raised surface of resist and a second of said nanostructure dual layers is on an inclusion in said resist. 
     
     
       2. The nanotag of  claim 1 , comprising a layer of polydimethylsiloxane (PDMS) and/or a layer of sol-gel. 
     
     
       3. The nanotag of  claim 1 , wherein said resist shows a surface consistency indicating casting or molding. 
     
     
       4. A nanotag comprising a metallic outer surface layer, the metallic outer surface layer comprising a dual layer of nanostructures which, when illuminated with a predefined illumination, provide a predetermined unique optical pattern, wherein a first of said nanostructure dual layers is on a raised surface of resist and a second of said nanostructure dual layers is on an inclusion in said resist, wherein said resist shows a surface consistency indicating casting or molding. 
     
     
       5. A method of providing a secure nanotag for identification and authentication, the method comprising:
 obtaining an image for identification; 
 providing a seed; 
 using the seed to seed a process for generating a phasemap that reproduces said image as a hologram; 
 terminating the process after a specified number of iterations; 
 using the phasemap to manufacture a nanotag surface to produce said hologram; 
 thresholding the hologram to provide a predetermined number of brightest pixels; and 
 providing a fingerprint for said nanotag that identifies a pattern produced by said brightest pixels, the fingerprint being for authentication. 
 
     
     
       6. The method of  claim 5 , wherein said image is a barcode comprising a message. 
     
     
       7. The method of  claim 5 , wherein said nanotag surface is contoured as a patch dipole nanoantenna reflectarray. 
     
     
       8. The method of  claim 5 , comprising affixing said nanotag to a product or packaging and separately distributing said fingerprint. 
     
     
       9. The method of  claim 5 , comprising manufacturing the nanotag surface to produce a hologram at a predetermined distance. 
     
     
       10. The method of  claim 5 , further comprising interrogating said nanotag by applying a laser beam to said nanotag and photographing said hologram. 
     
     
       11. The method of  claim 10 , wherein said image is a 2D barcode, the method comprising reading said barcode from said photograph. 
     
     
       12. The method of  claim 11 , wherein said fingerprint comprises a sequence of coordinates of said brightest pixels, the method comprising thresholding said photograph to find said predetermined number of brightest pixels and comparing said pixels to said coordinates. 
     
     
       13. A nanotag comprising:
 a surface comprising an implementation of a phase map to project an image as a hologram; 
 the surface further comprising a speckle pattern of brightest pixels, the speckle pattern being unique to a seed number used to generate said phase map. 
 
     
     
       14. The nanotag of  claim 13 , wherein said surface comprises a patch dipole nanoantenna reflectarray.